Heating plant



July 18, 1944.

O. H. DlCKE HEATING PLANT Filed Nov. 21,

. 1941 2 Sheets-Sheet 1 o. HfDlcKE HEATING PLANT 2 sheets-sheet 2 Filed Nov. 21, 1941 Y e |K.. ),w Y R E*v mDMm N-H .o E Wmam IC V5. 1 @w B July 1s, 1944.

Patented July '18,1944

[UNITED STATE-s PATENT orricia,v

"11] j f omen. piene-acometer. N. rr snplleeuonrzevember-z1,' mnseem Nll naar `(cussm This vinvention relates to improvements 'in heatingjlplants,.particularly to sucheplants' of the hot air type in *which *a blower iis employed at times toprom'te circulation'of the'airirom the V.furnace tothe spacetobeheated andfthe'return of air therefrom'to the furnace. l

In :such vheating `plants it is `frequently desired to remploy a `illter, -a humiditying device, and/or other devices to illter and/or .humidity the air. Buch devices, particularly nlters,

create substantial resistance tothe flow otthe Y air. Ii' therefore, in such a fplantfthebiower is not operating the 'resistance Zto yairilurwds-so great 'thatcirculation by convectionvis impossible. If .a byfpass is provided around thefillter tained when the blower yit not operating itis customary to provide :a valve ordamper of .some4 kind which must be fopen when natural drafts or convection'circulation is desired but which must be closed when the blower "is in'operation to prevent the air delivered `by they blower from being driven in the reversey direction y'through the cold lair return duct into the apartment. Such valves or dampers and the necessary means for operating them add to the cost of the in stallation and oi' operation andincrease `the cost of maintenance.

It is an'object of the present invention'to provide an improved heating.' Vplant `comprising Y a furnace, hotra'ir distribution conduits, a cold air return conduit, a nlteror other air conditionv partly in section `a heetingfpient embodying the Y invention; i Y

Fig. `2V is a partial partly sectional view. taken I' l-along the lline 1-2 o! Fig. `ll-lookingin thedirection of the arrows:

Fig. i3 shows a side view partly in section of a l modification; L

vlll so that circulation by convection can be ob-V F154 ne' pien view partly in section 'f the' form of device shown in Fig. 3 and Flg.,.5 is a cross-sectional view taken on the line l-Iof Fig. 3 `looking in the direction oi'the arrows.V Y l .A

Referring to said drawings, the numeralll represents generally a `hot air furnace which may-be of :conventional construction provided vwith a i'iue pipe l2, anzfairintake or drait'damper Y il, landa check damper Il. `Buch furnaces usually have a nre pot such las Il and are-sur# i. rounded by a casing such as II and usually have a'returnair conduit such as I1. `.Ils usual,

one or more hot air conduits il'leadl frointhe' upper part ofthe Vfurnace casing or bonnetto the various rooms to be heated, the air` entering the room through registers such as Il. Thev numeral'lindicategsuch a room.

The numeral 2l indicates va coldairreturnVV vgrate connecting to a cold air 'return Vconduit .such as 22. In the form shown, thelower part ing device and a blower. and' a Vby-pass around the blower and filter, the parts being so arranged that the air delivered by the .blower creates an injector leiIect whichv tends to draw vair through the by-pass in thedirection toward the furnace when the blower is 'in operation soy that it isfnot possible tor air to be blown in a reverse `directionthrough the by-pass-.and the cold air return into the apartment.

Another object ist to; provide such a ldevice in which the parts are 'so arranged and proportioned that a minimum amount oi' airor noiair at all is drawn through the by'dpass "by injector action when the blower is in operation softhat all 'or substantially allv of the; air being circuof this; conduit` is completelyV closed by,V one :or more filter slabs, such .as IIythus providing a space 2l in which is yhouseda blower Il driven by an electric motor l2l by means'otth'e belt 28.

One or both` ends loi.' said .blower are open to take inair from the space 2l.

As shown, a by-pass conduit 2l is provided leady'ing Vfrom thecoldf air return -du'ct 22 and .connectingV with thev conduit I1.. The by-pass 28 connect; with the duct 12, although it is also possibleto have it connect -directly to the :room j .space 2l. 2l 'indicates an injector plate pref- :erablypivoted as at Illfandheld in the desired position'o'f adjustment Vbyfany suitable means lated must pass through the filter or -otherair conditioning device. y f l. v y These and other objects will become apparent from the following descriptiontaken in connection with4 the attached drawings showingv several illustrative embodimentsro! the'invention and wherein:

Fig. 1 shows moreV orless` schematically and stantial-velocity throughthe throat formed under Athe injector ,plate .29. At this NpointY the cross-sectional area is substantially reduced vso that the velocity Aof flow vis sub'- stantially-increasedt Therefore, in accordance with Bernoullis law, pressure at this/point' is very:Y substantially reduced .preferably Veven slightly below atmospheric pressure so vthat there'is no pressure available 'tor drive airupwardlythrough theby-pass 28""and, in fact, a

Thevoperation of the'device'is as `follows: when -K Vthe blowerjyis` operatingl it delivers air at a subperature.

certain small amount of air is probably usually drawn downwardly through by-pass 28.` Beyond the throat the cross-sectional area ofthe passage increases substantially. This results in a reduction in velocity and a large part of the kinetic energy of velocity will, in accordance kwith Bernoullis law 4be converted into potential energy, resulting in an increase in pressure as the air'enters the bottom of the furnace casing, producing the desired pressure for causing circulation. Y f

It willbe noted that when the blower is not in operation there is a clear path around the?V vection will take place while the blower is not in operation so that heat is being carried from the furnace into the roomfeven while the blowerv is not operating, resulting in 'even room, temlAny desiredmeans maybe employedf'orkcontrolling the operationof the blower driving motor 2l, such as a hand'operated switch.- Iny Fig. 1

is shown one manner k"of :control which may in some `cases be' desirable, comprising a' ,thermostat 38 in the room to be heated and a thermostat in the 'bonnet of the furnace. vTheconductor 33 is connected from a source of electric supply and to the thermostat from which the conductor 35 leads to the" motor 25 from which'thefconductor 3B leads to the'` thermostat rIl from which the conductor 38 leadsto the sourcefof power.

supply. The thermostat. is preferablyV so ar' ranged as to closethe' circultvwhenever'theroom "temperature drops'below a' Vcertainl point, Ysay 70 F.,fand the thermostat 34' is'so arranged as Uto open the circuit whenthe bonnettemperature isa-below I'a predetermined temperature; such as 100 F. vIt will'be'seen'therefore'that whenever the temperature inthe room is below '70 andthe .temperature in thefbonnet is? above 100",y vthe blower will be operated. If, however, the room temperature rises to v'70.or if the bonnet temperature falls below100 F., the motor and blower would in turn control a switch between the conductors 3B and so that thefblower could operate only when the' thermostat'calls for heat.

; Such a system has however not been shown because it'does not form a-.partof the presentinvention which will Vbe useful in any forced fluid i n circulation system in which some means arel pro- .vided' to cause intermittent operation of'- the blower or other fluid pumps 'Y In the modified form shown in Figs. 3,'4 and 5 the corresponding parts have been :designated by the same numerals as those employed in Figs;

l and 2, the subscript a being added. :The principal difference in construction is that in this case'a separate housing 40 is employed which contains the blower ormay comprise Vthe hous-V ing ofthe blower itself, the-top of which is closed by the filter members 21a.

` The housing is smaller than the enclosing casing'of conduitV 22a `so as to provide aubypass passage around all sides of housing 40. `'Said housingflll is gradually contracted and terminates in aV nozzle portion '4I y filter through the passage 28 so that natural conf f Ziff v 2,353,815

substantially inlineywith'the narrowest portion llb of the passage Ila. In this way, an even more accentuated injector effect can be secured.

It will be noted that the constructions shown and described will serve admirably to accomplish f the objects stated above. It is to be understood, however, vthat the constructions disclosed above are intended merely as illustrative of the invention and not as limiting as various other modifications therein may be made without departing from the invention as defined by a proper interpretation of the claims which follow.

I claim:

l, I n a combined forced draft and natural draft air circulator for hot air heating systems ."employing" hot air furnaces comprising; a boxlike main casing yterminating in a conduit having anarrow'neck near said casing and flaring out ,to aV larger cross-'sectional area toward its free end, which free end may bev connected `into the lower'end of suchfurnace; said casing having 'an opening which may be vconnected with a. cold air return Yconduitof said system j van intermit- Qtently operated blower lin. said main casing consisting Aof a' second. casing having an inlet opening and having an outlet openingterminating Y substantially in the neck of said conduit but of ja smaller 'cross-sectional. area than said neck,

and of a fan in said second casing which when operated drawns air through'said inlet opening and-projects it through said outlet opening into 'saidcondum anda inter located walter only the air passing;y through saidinlet opening of said second casing; whereby when said blower is Voperating thefinertia ofthe stream of blower propelled iilteredair as it spreads during its .passage through ,said conduit rand toward said furnace causes a partial vacuum toV be created aboutsaid stream in said conduit which :vacuum tends'tojfdraw unfiltered` air' through the bypass Vformed betweenrsaid outer casingand said second casing intosaid conduit and `whereby un Vfiltered gravitationally propelledv air may -flow freely through Vvsaid by-pass when saidlfan is'not operating., pu

2. In arheating plant, `a wfurnace for yheating air to be circulated to the space tobe heated, an

- intermittently operating blower including a housing havingan inlet and an outlet opening, a fllter located so as to illter only the .air passing through Vsaidhousing, a conduit of Vgradually increasing cross-sectionalarea extending .from said outlet opening to the. furnace, at least one hot air conduit extending from ,the furnacey tofthe space to Vb e heated, a coldvairconduit connecting from 1 'saidspace tofsaid inletopening and a -by-pass Yconnecting from said cold air conduit to said rst mentioned conduit and around said housing andvfilter, the said first mentioned conduit having a restricted.crossfsectional area near said housing where said by-pass joins it followed by said gradually increasing cross-sectional area, so that the air flowingmthrough said housing and filter ltends to draw air through said by-pass toward thef furnace, .whereby when the blower is tnot operating airmay be drawn from saidspace to thefurnace throughsaidcoldfair'conduit said byfpass and said first mentioned conduit by' con- Y 3. In a `combined :"forc'ed vdraft 'and natural draft air circulator for a hot lair heating system employingv a hot al1-furnace comprising; `an intermittently operating blower including a housfing having ani'nlet-openin'gand an outletopening, a conduit structure of gradually increasing cross-sectional area extending from said outlet opening to such furnace land having its most restricted cross-sectional portion where it joins said outlet opening, a by-pass in multiple with said blower housing and extending from said lnlet opening to join said conduit structure at its most restricted cross-sectional portion, a lter located so as to illter the air passing through said inlet opening but not the air passing through said by-pass, whereby when said blower is operatinl'the inertia. of the stream of blower propelled air as it spreads during its vpassage through saidconduit structure and toward such furnace y causes a partial vacuum to be created about said stream near said most restricted portion in said conduit structure which vacuum tends to draw unltered air through said by-pass and into said conduit structure and whereby due to the heat of such furnace gravitatlonally propelled unltered air may iiow freely through said by-Dass and conduit lstructure to auch furnace when said blower is not operating. j Y

. OSCAR H; DICKE. 

